The invention relates generally to the field of geothermal heating and air conditioning systems and in particularly to pipe systems used for in-ground heat exchange. The invention provides a system having in-ground conduit system which is simpler to install than previous conduit systems.
Geothermal heating and air conditioning systems, i.e. heat pump systems, are increasingly popular for efficient heating and cooling of loads, for example as part of a heating-ventilation-air conditioning (HVAC) system for buildings. Heat pump systems generally include heat exchangers thermally coupled to the load and to a heat source or heat sink, the heat exchangers being connected in a refrigerant or coolant loop which includes a compressor and an expander. The compressor raises the pressure (and therefore the temperature) of the refrigerant and the expander lowers the pressure, producing a lower temperature in the refrigerant.
In heating a load, a "ground source" heat pump, which has the source/sink heat exchanger thermally conductively coupled to the ground, can extract a virtually limitless supply of thermal energy from the earth and transfer the energy to the load. A heat pump cools a load by extracting thermal energy from the load and transferring it to the earth for dissipation therein. In this manner the ground functions as either a heat sink or heat source. Modern day heat pumps for HVAC systems are equipped with reversing features such as valves to arrange the flow of refrigerant so that they may both heat and cool the load, as needed.
A ground source heat pump requires a subterranean heat exchanger. While it is possible to use intermediate heat exchangers for transferring heat through thermally coupled fluid flow paths or the like, preferably the refrigerant or coolant is pumped through the pipes by the compressor and serves directly as the carrier for conveying the thermal energy to or from the ground. Thus, extra heat transfer losses, such as those inherent in ground water source systems, are avoided. The coolant is relatively heated by compression and cooled by expansion, leading to the respective heat exchangers, thereby raising the temperature of the hot side heat exchanger above the temperature of the load and lowering the temperature of the cool side heat exchanger below the temperature of the source, whereupon heat transfer occurs. Compression and expansion normally include a change of state of the coolant between liquid and gaseous states.
The load heat exchanger is typically above ground and the ground heat exchanger is preferably well below the surface of the ground. Connecting pipes for the ground heat exchanger, and the pipes defined by the heat exchanger itself, can be horizontal, vertical or slanted. A typical installation may include combinations of these orientations, depending upon particular design criteria. The problem encountered in the installation of the pipes, particularly in a vertical or slanted orientation, is the tendency of the pipe to rise upward in the vertical or slanted hole after installation.
Generally, in installation of the slanted or vertical pipe, a bore-hole is drilled and a double run of pipe connected by a U-bend fitting is inserted into the bore-hole. The pipe is usually inserted into the bore-hole by utilizing weights attached to the U-bend fitting to force the pipe into the hole. After the pipe is inserted, the weights are usually retrieved using a line attached to the weights. However, when the steel bars used for weights to force the piping into the well are retrieved, the piping has a tendency to come out of the well with the weights.
It would be advantageous to have a low cost method of resolving the foregoing problem.